FI stop positions

[hiddewie]

Fixes #630

Changes:

• Support for T-144 and new T-144 signs
• Support for T-270 - T272 signs for stop positions
• Support for T-273 - T275 signs for train compositions

Tampere (http://localhost:8000/#view=15.94/61.498645/23.774113/-43.1&style=signals):

Nokia (http://localhost:8000/#view=16.44/61.481815/23.501053&style=signals):

Note some signals have multiple stop signals tagged on a single node, which does not work.